I think my fish has Velvet so I bought salt to treat it. But the bag has no instructions !!! Just tells me how much to use. Do I put it in there while he's in there, or take him out first. I'm clueless ! Pleas help !!

Dissolve 1 tsp of AQ salt per gallon before adding it to your water, then slowly condition your fish to get him/her used to the new water. Make sure he/she is in a heated tank to speed recovery. When using AQ salt, it is best to do 100% water changes as the salt does not evaporate.